She added: "It is relatively simple to count our larger animals but the smaller ones can prove more challenging as they are prone to hiding or moving.

"Fish in particular are tricky to tally up as they move continually."

Last year saw the silverback gorilla Ya Kwanza leave the wildlife park.

He had been there since 1993, but because he had not bred for eight years, he was sent to his new home with a bachelor group of gorillas at La Vallee des Singes, just south of Poitiers, France, in July.

He was replaced by Badongo, a male gorilla born at La Vallee des Singes.

Other new arrivals in 2011 included 22 orange tailed skinks rescued following the invasion of Flat Island, Mauritius, by the predatory Indian musk shrew.